1. Technical Field
Embodiments disclosed herein relate generally to the field of borehole formation testing and acoustic logging. More particularly, embodiments disclosed herein are related to measurement of the speed of sound in a formation fluid.
2. Description of Related Art
In the field of borehole acoustic logging for oil and gas exploration and extraction, in situ measurement of physical properties of earth formations is desired. Earth formations typically include different types of solid substrates in a variety of physical arrangements such as layers, rock beds, sand embankments, and others. The solid materials may be mixed with fluids and suspensions including mud, water, oil, and gas among other components. Due to the complexity of earth formation compositions, a wide variety of parameters is collected to obtain properties such as Gas-Oil Ratio (GOR), or shear wave anisotropy. GOR is a volumetric measure providing the ratio of gas to oil at atmospheric pressures, once the liquid is extracted from the “downhole” formation at high pressures. The shear wave anisotropy is related to the depositional history and the amount and maturity of hydrocarbons in a gas shale. One of the parameters used to extract formation properties is the formation fluid density. However, to obtain more accurate values of the physical properties of the earth formations, the speed of sound in the fluid component is a desired parameter. For example, a linear relation has been found between GOR and the fluid speed of sound.
Therefore, it is of practical importance to accurately measure formation fluid speed of sound in addition to other parameters used to determine physical properties of the soil formation.